百钱买鸡问题：一百个铜钱买了一百只鸡，其中公鸡一只5钱、母鸡一只3钱，小鸡一钱3只、问一百只鸡中公鸡母鸡、小鸡各多少。?(100 yuan to buy chicken problem: one hundred copper coins bought one hundred chickens, of which 5 were cock, 3 for hens, 3 for chickens, one hundred for roosters, hens and chicks.)